World’s First Population-Level Microbiome Study Reveals Links Between Lifestyle and Gut Flora

02 May 2016 --- The Flemish Gut Flora Project, one of the largest population-wide studies on gut flora variation among healthy volunteers, has presented its first major results. Through the analysis of more than 1,000 human stool samples, a team of researchers led by Professor Jeroen Raes of VIB-Flanders Interuniversity Institute for Biotechnology (VIB/VUB/KU Leuven) has identified 69 factors that are linked to gut flora composition. 

The project’s fundamental insights will be published in the upcoming issue of the academic journal Science. These results provide important information for future disease research and clinical studies. 

Raes told NutritionInsight: “I think understanding the natural variation in the ‘normal’ population and what affects it is essential for designing nutrition-based microbiota modulation products for disease treatment.”

“Our work is actually just the start – there is a lot of work that still needs to be done to identify those compounds/ingredients that affect microbiota composition and figure out how they work. With this work we have the ‘map’ of healthy microbiome space – now we need to identify how to move people around on that map.”

The Flemish Gut Flora Project was initiated by Professor Raes in 2012. Together with his team, he aimed to map the gut flora composition of around 5,000 volunteers in Flanders (Belgium). The purpose of this endeavor was to investigate links between the human gut flora and health, diet, and lifestyle.

Titled “Population-level analysis of gut microbiome variation”, Professor Raes’ study has identified 69 factors associated with gut flora composition and diversity. Most of these covariates are related to transit time, health, diet, medication, gender, and age. Integration of the Flemish Gut Flora Project results with other data sets gathered around the world revealed a set of 14 bacterial genera that make up a universal core microbiota present in all individuals.

Professor Raes stated: “Our research has given us a tremendous amount of new insight into the microbiota composition of normal people like you and me. This makes the Flemish Gut Flora Project unique, since the majority of previous studies focused on specific diseases or featured a significantly smaller geographical scope.”

“However, analyzing the ‘average’ gut flora is essential for developing gut bacteria-based diagnostics and drugs. You need to understand what’s normal before you can understand and treat disease”.

Stool transit time showed the strongest association to gut flora composition. Also diet was an important factor, with most associations related to fiber consumption. One of the many surprising findings was the association of a particular bacterial group with a preference for dark chocolate - “The Belgian chocolate effect”! 
“As many readers might expect, we also found an association between gut flora composition and beer consumption,” Raes noted. 

Other project results incite deeper investigation, such as the relationship between the gut flora and factors linked to oxygen uptake capacity. Professor Raes explained “These results are essential for disease studies. Parkinson’s disease, for example, is typically associated with a longer intestinal transit time, which in turn impacts microbiota composition. So to study the microbiota in Parkinson’s disease, you need to take that into account. These and many other observations can help scientists in their research into future therapies.”

Although the Flemish Gut Flora Project has enormously enriched knowledge on gut flora composition, it only explains 7% of gut flora variation. Therefore, an enormous amount of work still needs to be done in order to sketch out the entire gut flora ecosystem. 

The Raes Lab estimates that around 40,000 human samples will be required just to capture a complete picture of gut flora biodiversity. In other words: we are only seeing the tip of the iceberg. And although the VIB team revealed a wide range of associations, further research is required to unveil what is cause and what is consequence.

The Raes Lab is already planning follow-up studies, including new large-scale research projects that will explore the evolution of gut flora over time. More volunteers are now being recruited for this long-term study. 

The more people willing to participate, the faster VIB will be able to unveil new insights into the relationship between the trillions of microbes in the human body and our health. 

by Kerina Tull